This application relies for priority upon Korean Patent Application No. 2001-87114, filed on Dec. 28, 2001, the contents of which are herein incorporated by reference in their entirety.
The present invention relates to an apparatus for fabricating a semiconductor device used in a wafer cleaning process and, more particularly, to an apparatus for drying a wafer subjected to a cleaning process.
As semiconductor devices are continuously scaled down, the wafer cleaning techniques have been diversified and increasingly significant. Particularly in a process for fabricating semiconductor devices having a fine structure, particles attached to a cleaned wafer, static electricity, watermarks, and linear particles have a great effect on subsequent processes. Therefore, what is needed is a wafer drying process.
There were suggested a spin dryer and an IPA vapor dryer. In drying a wafer, the spin dryer uses a centrifugal force while the IPA vapor dryer uses a low vapor pressure of isopropyle alcohol (IPA). However, the dryers cannot completely remove watermarks that occur on a wafer surface or between patterns. In order to avoid this problem, a Marangoni dryer has been widely used. The Marangoni dryer uses a difference between surface tenses of the IPA and water.
A drying process using the Marangoni effect will now be described in brief hereinbelow.
After wafers are rinsed out by de-ionized water (hereinafter referred to as xe2x80x9cDIWxe2x80x9d), the IPA vapor is fed to an upper interior space of a rinsing bath and the DIW is slowly withdrawn. Thus, the water is eliminated from a wafer surface. When the DIW is completely drained, the nitrogen of high temperature is fed thereinto to evaporate the DIW remaining on the wafer surface. Unfortunately, the evaporated DIW and residues including particles are not fully issued out. They cause the irregular liquid flow (turbulence) in the rinsing bath together with the nitrogen, so that the wafer surface is not uniformly dried and the water remains at a portion contacting with a wafer guide. In addition, since the Marangoni dryer cannot fundamentally prevent oxygen from reacting on the wafer, it cannot suppress formation of an oxide layer.
A feature of the present invention to provide a wafer drying apparatus that fundamentally prevents oxygen from reacting on a wafer surface during a wafer drying process to suppress formation of an oxide layer.
Another feature of the present invention is to provide a wafer drying apparatus that improves a wafer drying efficiency.
Still another feature of the present invention is to provide a wafer drying apparatus that suppresses the turbulence in a processing bath. To achieve these features, the present invention provide a wafer drying apparatus in which a gas used to dry a wafer smoothly flows from an upper part to a lower part of a processing bath and is smoothly discharged to improve a wafer drying efficiency. This wafer drying apparatus includes an injection port for injecting a dry gas into the processing bath to eliminate water remaining on a wafer, decompression means for decompressing an inside of the processing bath, and an exhaust pipe through which the injected dry gas and residues including vapor dried by the dry gas are exhausted. The exhaust pipe communicates with a drain pipe for draining a process solution filling the processing bath. The drain pipe is comprised of a first drain pipe for draining the process solution and a second drain pipe for draining the process solution slower than the first pipe. The exhaust pipe is connected to the first drain pipe.
The wafer drying apparatus further includes a sealing member for sealing between the processing bath and the cover. The sealing member may be an O-ring or a gasket.
According to another aspect of the invention, an apparatus for drying a semiconductor substrate includes a chamber having a processing bath with which a liquid is filled and a cover mounted upon the processing bath, a gas distributor for spraying a gas for drying the substrate from an upper part of the processing bath, a liquid flow system for supplying a liquid flow into the processing bath so as to clean the substrate and for draining a liquid from the processing bath, decompression means for exhausting air in the chamber, and means for exhausting the gas supplied into the chamber.
The gas distributor includes first and second nozzles mounted upon the cover. The decompression means includes an exhaust port formed at the cover, a second exhaust pipe connected to the exhaust port, and a valve for shutting on/off the first exhaust pipe. The liquid flow system controls the liquid flow and drain together with the gas distributor to achieve the Marangoni effect. The apparatus further includes means for forcibly exhausting the gas supplied into the chamber. The forcibly exhausting means includes a first exhaust pipe connected to the drain pipe and an on/off valve for shutting on/off the second drain pipe.